Schools are required to have functional, accurate NPCs on their websites. If they don’t, that’s on them.
Students absolutely should use their ED chit if the school looks affordable per the NPC. Your argument continues the fallacy/advice of low SES students not using ED, which in turn keeps lower SES families from applying in an advantaged admission round. Low SES students should be encouraged to use these advantages, just like high SES students have been.
Bottom line, if inadequate financial aid is ultimately provided (or there’s a changed financial situation) that’s reason for an applicant to back out of the legally unenforceable ED agreement…no questions asked.
No college wants a student to attend who doesn’t want to be there and/or doesn’t find it affordable. The ED police are not coming. Colleges are not blackballing GCs or HSs of students who back out of ED agreements.